Added Map and MapError

MaybeError/MaybeError.csproj

@@ -8,7 +8,7 @@
 
 	<PropertyGroup>
 		<PackageId>MaybeError</PackageId>
-		<Version>1.1.0</Version>
+		<Version>1.2.0</Version>
 		<Authors>Amatsugu</Authors>
 		<PackageDescription>Errors as values</PackageDescription>
 		<RepositoryUrl>https://github.com/Amatsugu/MaybeError</RepositoryUrl>

MaybeError/MaybeExtensions.cs

@@ -37,6 +37,20 @@ public static class MaybeExtensions
 		return predicate(maybe.Value);
 	}
 
+	public static ValueMaybe<T2, E> Map<T, T2, E>(this IValueMaybe<T, E> maybe, Func<T, T2> map) where T : struct where T2 : struct where E : Error 
+	{
+		if (maybe.HasError)
+			return maybe.Error;
+		return map(maybe.Value);
+	}
+
+	public static ValueMaybe<T, E2> MapError<T, E, E2>(this IValueMaybe<T, E> maybe, Func<E, E2> map) where T : struct where E : Error where E2 : Error
+	{
+		if (!maybe.HasError)
+			return maybe.Value;
+		return map(maybe.Error);
+	}
+
 
 	public static T ValueOrDefault<T, E>(this IMaybe<T, E> maybe, T defaultValue) where E : Error
 	{
@@ -71,4 +85,18 @@ public static class MaybeExtensions
 		return predicate(maybe.Value);
 	}
 
+	public static Maybe<T2, E> Map<T, T2, E>(this IMaybe<T, E> maybe, Func<T, T2> map) where E : Error
+	{
+		if (maybe.HasError)
+			return maybe.Error;
+		return map(maybe.Value);
+	}
+
+	public static Maybe<T, E2> MapError<T, E, E2>(this IMaybe<T, E> maybe, Func<E, E2> map) where E : Error where E2 : Error
+	{
+		if (!maybe.HasError)
+			return maybe.Value;
+		return map(maybe.Error);
+	}
+
 }

MaybeErrorTests/MaybeTests.cs

@@ -115,4 +115,40 @@ public class MaybeTests
 		value = new InvalidOperationException();
 		Assert.That(value.AsOrDefault(v => v.Length, -4), Is.EqualTo(-4));
 	}
+
+	[Test]
+	public void MapTest()
+	{
+		Maybe<string> value = "Test";
+		var valueMapped = value.Map(v => $"A{v}");
+		Assert.That(valueMapped.HasValue, Is.True);
+		Assert.That(valueMapped.Value, Is.EqualTo("ATest"));
+	}
+
+	[Test]
+	public void MapTestError()
+	{
+		Maybe<string> value = new Error("Err");
+		var valueMapped = value.Map(v => $"A{v}");
+		Assert.That(valueMapped.HasError, Is.True);
+	}
+
+
+	[Test]
+	public void MapErrorTest()
+	{
+		Maybe<string> value = "Test";
+		var valueMapped = value.MapError(v => new Error($"A{v}"));
+		Assert.That(valueMapped.HasValue, Is.True);
+		Assert.That(valueMapped.Value, Is.EqualTo("Test"));
+	}
+
+	[Test]
+	public void MapErrorTestError()
+	{
+		Maybe<string> value = new Error("Err");
+		var valueMapped = value.MapError(v => new Error($"A{v.Message}"));
+		Assert.That(valueMapped.HasError, Is.True);
+		Assert.That(valueMapped.Error!.Message, Is.EqualTo("AErr"));
+	}
 }

MaybeErrorTests/ValueMaybeTests.cs

@@ -115,4 +115,40 @@ public class ValueMaybeTests
 		value = new InvalidOperationException();
 		Assert.That(value.AsOrDefault(v => v.ToString(), "err"), Is.EqualTo("err"));
 	}
+
+	[Test]
+	public void MapTest()
+	{
+		ValueMaybe<int> value = 1;
+		var valueMapped = value.Map(v => v + 1);
+		Assert.That(valueMapped.HasValue, Is.True);
+		Assert.That(valueMapped.Value, Is.EqualTo(2));
+	}
+
+	[Test]
+	public void MapTestError()
+	{
+		ValueMaybe<int> value = new Error("Err");
+		var valueMapped = value.Map(v => v + 1);
+		Assert.That(valueMapped.HasError, Is.True);
+	}
+
+
+	[Test]
+	public void MapErrorTest()
+	{
+		Maybe<int> value = 1;
+		var valueMapped = value.MapError(v => new Error($"A{v}"));
+		Assert.That(valueMapped.HasValue, Is.True);
+		Assert.That(valueMapped.Value, Is.EqualTo(1));
+	}
+
+	[Test]
+	public void MapErrorTestError()
+	{
+		ValueMaybe<int> value = new Error("Err");
+		var valueMapped = value.MapError(v => new Error($"A{v.Message}"));
+		Assert.That(valueMapped.HasError, Is.True);
+		Assert.That(valueMapped.Error!.Message, Is.EqualTo("AErr"));
+	}
 }